Colorimetric Determination of Formaldehyde under Mild Conditions

Abstract

IN the course of work on the neutralization of formaldehyde in living bacterial cultures, it was found that the Hantzsch reaction between acetylacetone, ammonia and formaldehyde proceeded so readily at pH 6 that it afforded a good method of estimating microgram amounts of the latter. The yellow colour due to the formation of diacetyl-dihydro-lutidine is fully developed in two hours at room temperature, the molecular extinction being 8,000 at 412 m. The reaction will be fully described elsewhere; but a suitable reagent is known to be M/20 acetylacetone and M/30 acetic acid in molar aqueous ammonium acetate. The only unexpected interfering substance found was sulphite. © 1952 Nature Publishing Group.